Big Valve Heads

[88liam]

Afternoon,

105 green Cloverleaf, did the 105 have big valve heads or
was it the gold cloverleaf 115bhp, looking at building an
engine with a 1500 block and 1700 crank for road use,
can valves from a 1700 fit into the 1500 heads???

Liam

[Veesix75]

I thought the 1500 heads with 40mm valves were on the 33 not sud.

The mechanical and hydraulic valves are different lengths.

Just to confuse you further (sorry), I have a 1700 8v mild road with 40mm valves, and the same with 38mm valves (40mm machined down) and the latter is the stronger engine, same bhp but more torque.

[PETROLHEAD]

If i recall correctly, the 40mm valves first appeared in the early 1.7 sprint, possibly the series 2 33 aswell but unsure, but i think they would have to have been sourced from the much rarer these days mechanical tappet motor.

Most later 1.7 motors went hydraulic of course so i think you're correct in them not being suitable Tim

many 40mm valves found their way into 105 type heads in various class 1.5l sud race cars, although most of them shouldn't have!


does that sound about right?

[Veesix75]

Just remembered , John at justsuds had a lad of bits off me years ago, included were some Brunswick class F heads, might have been 1500 flat heads, but lightly ported, torquey and and a punchy power band at about 4K rpm. He might still have them if you have dished Pistons. 38mm valves but it went well.

[sudboy1490]

Hi Liam I was told you only need 40mm valves if your going wild cams in a full race set up. What veesix says makes sense mate.

[PETROLHEAD]

I had a 1.5 gc motor with 40mm valves, and a little port matching, no serious metal removal. Stock cams, but choked down 40mm carbs, and it was one of the best I've ever had,

It flew to be honest, was much livelier than the gold cloverleaf 1.7 sprint i had at a similar time.

I remember rushing to catch Bryan's qualifying session at Snetterton after i got caught at sutton bridge for an eternity, it got caned all the way down there, and on the final sections of dual carriage way i had 120 plus on the tomtom still pulling!

I loved that car, it pulled so well!

[88liam]

Thanks Guys,

I have a complete 105 engine and a 1.7 engine in bits,
read some were that a 1500 block with a 1.7 crank
would give more torque than a 1700 block with 1.5 crank, anybody verify this.
is the 1.7 8v crank the same as 1.7 16v crank. ( is the 16v cross drilled)?

Liam

[PETROLHEAD]

Hi liam

Not sure about the first query, but i believe the 16v had some improvement in the final finish detailing, maybe the surface treatment, i can remember exactly but its commonly thought of as better.

[BS25]

With regards to big valves it's all part of a combination of the re-shaping of the ports and cam profile. Standard 1.7 engines went upto 40mm as mentioned above so for a similar size engine and fast road/rally/race cams larger valves are required - 40mm isn't enough to flow what the race cams and ported heads provide. My 1800 8 valve had some very special heads including 45.1mm inlets - the exhausts were obviously bigger than standard too - it was quite a squeeze! To show the benefits of going 16v, the inlets on my race engine are 34mm each - so 68mm of valve opening v 45mm (8v) per cylinder.

40mm is fine for fast road/mild race (with suitably subtle porting and cam profile).

[Spacenut]

I read somewhere that a 1500 block with a 1.7 crank
would give more torque than a 1700 block with 1.5 crank, anybody verify this.

That is my understanding. When you think about it, it makes sense - a 1700 block with a 1500 crank would create a very oversquare bore/stroke ratio, which is good for top end power. A 1500 block with a "stroker" 1700 crank would give the opposite, long stroke with a relatively narrow bore, which is better for torque.

The latter option doesn't appear to be as popular these days, but my as-yet unfitted Alfatune engine is built to this specification, 1500 block with 1700 crank and new pistons giving 1600cc.

Lauren

[88liam]

With regards to big valves it's all part of a combination of the re-shaping of the ports and cam profile. Standard 1.7 engines went upto 40mm as mentioned above so for a similar size engine and fast road/rally/race cams larger valves are required - 40mm isn't enough to flow what the race cams and ported heads provide. My 1800 8 valve had some very special heads including 45.1mm inlets - the exhausts were obviously bigger than standard too - it was quite a squeeze! To show the benefits of going 16v, the inlets on my race engine are 34mm each - so 68mm of valve opening v 45mm (8v) per cylinder.

40mm is fine for fast road/mild race (with suitably subtle porting and cam profile).

Thanks Bryan, weighing up the options for a fast road car, more concerned about torque and the way
it revs than bhp. are all 1700cc heads and valves the same regardless off mechanical or hydraulic lifters?
Thinking off using 1700cc heads or 1700 valves into 105 heads ported and polished. standard 105 cams, a 1500cc block slightly overbored,
ligtened and balanced, a 1700cc crank with uprated bolts, 40 carbs and a standard 1700cc exhaust. thinking this would give
me about 120/130bhp, 7500rpm and good torque. i have most of the bits and it would not cost a fortune.
all advice appreciated.

Liam

[88liam]

I had a 1.5 gc motor with 40mm valves, and a little port matching, no serious metal removal. Stock cams, but choked down 40mm carbs, and it was one of the best I've ever had,

It flew to be honest, was much livelier than the gold cloverleaf 1.7 sprint i had at a similar time.

I remember rushing to catch Bryan's qualifying session at Snetterton after i got caught at sutton bridge for an eternity, it got caned all the way down there, and on the final sections of dual carriage way i had 120 plus on the tomtom still pulling!

I loved that car, it pulled so well!

Hello Shrew , any idea of the bhp and torque figures?

Liam

[Veesix75]

Depending on overall tune, a pair of 36mm carbs on 32/34 chokes would probably be enough.

I'd look for a balance of torque and top end, and stick in a S2 1500ti box, so 110mph to poss 120mph redlining in 5th but quick though the gears.

[88liam]

Depending on overall tune, a pair of 36mm carbs on 32/34 chokes would probably be enough.

I'd look for a balance of torque and top end, and stick in a S2 1500ti box, so 110mph to poss 120mph redlining in 5th but quick though the gears.

What final drive ratio is the s2 1500ti box ?

[PETROLHEAD]

Hi liam

No, sorry, i have no idea what the power or torque output was, i doubt it was anything impressive enough to have any bragging rights, but the way it drove was just brilliant.

I agree with tim on the right choice of gearbox too, in fact i believe that was the same or very close to the gearbox my sud was using. Nice ratios, and didn't lose a deal of excitement when used with bigger wheels either.

I miss that sud!

[Veesix75]

I've got the final drive and ratios written down , I'll dig them out. It's a step up from a 1200ti, but still 'close' enough to be quick through the gears if that's what you want. Probably work well with 14inch wheels.

[88liam]

Hi liam

No, sorry, i have no idea what the power or torque output was, i doubt it was anything impressive enough to have any bragging rights, but the way it drove was just brilliant.

I agree with tim on the right choice of gearbox too, in fact i believe that was the same or very close to the gearbox my sud was using. Nice ratios, and didn't lose a deal of excitement when used with bigger wheels either.

I miss that sud!

.
Hi Shrew; what size where your outlet valves; take it your inlet where 40mm; Liam

[PETROLHEAD]

You know what Liam, i don't think they were anything other than standard 105 head valves, i seem to recall that only the inlet valves had been upsized, which i believe was a fairly typical class c stunt, just sneaking in a little bit here n there!

the 1600cc engine, no matter how you get there, does seem to have earned quite a reputation, some call it the screamer due to its revving tendencies, but it can be an exciting engine if built properly i gather.

i hope this comes off for you mate, i just can't believe you haven't already got one,

you have one of just about every other size and shape, its odd you don't have this under your bench already bud!

[88liam]

You know what Liam, i don't think they were anything other than standard 105 head valves, i seem to recall that only the inlet valves had been upsized, which i believe was a fairly typical class c stunt, just sneaking in a little bit here n there!

the 1600cc engine, no matter how you get there, does seem to have earned quite a reputation, some call it the screamer due to its revving tendencies, but it can be an exciting engine if built properly i gather.

i hope this comes off for you mate, i just can't believe you haven't already got one,

you have one of just about every other size and shape, its odd you don't have this under your bench already bud!

Morning Shrew, you are correct

I purchased an engine from John at justsuds, apparently an ex alfatune engine, stripped the heads of yesterday,
spec as follows, adjustable pulleys, 1.5 block (85mm), pocketed pistons, 40mm inlet valves, 32mm outlet valves, inlet manifolds open up to
match 40mm webers, cams look standard, heads worked but not very smooth, looking a removing the sump
later this week to check the internals, plan is to fit a 1700 crank.

Liam

[PETROLHEAD]

That motor sounds very similar to the one favourably referenced earlier, minus the crank, i think!

I loved it Liam!

[alfettagtam]

So what about a 1600 from a 146? I have one of these in my gymkhana car. I've been eying it up as a nice engine for the sud. Switching it over to carbs - 40mm from a 33 perhaps?

Anyone done this? Standard, how much different to a 1500?

[sudboy1490]

Am i right in thinking that if you put a 1.7 crank in a 1.5 block you'll lose the 2.5mm clearance at the top of the bore? So if you use 1.5 flat heads on it you'll end up with virtually no compression chamber and a ratio of around 13:1. If so how do you over come this? Would you not need to use chambered heads on this set up and deck the block to get to 11:1?

[justsuds]

146 engine into a Sud is straightforward ish, - the flywheel housing may need to be changed if you want to use a mechanical fuel pump, or leave it and use an electric pump, and you may need to change the oil pump as some 145 / 146 engines didn't have the extension to drive the distributor, - which may or may not fit into the blanked off fitting in the top of the same flywheel housing. Carb manifolds will fit the heads no problem, but use 1.7 ones as they have an extension that covers the small cut outs in the inlet tracts for the injectors. The ribbed front pulley is a straight swop for a Sud pulley.
John.